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1987 Beef Cattle D
Special Report 800
May 1987
Agricultural Experiment Station
Extension Service
Oregon State University, Corvallis
TABLE OF CONTENTS
BEEF CATTLE DAY PROGRAM 1
USE OF IONOPHORES IN COMMERCIAL BEEF CATTLE PRODUCTION
Timothy DelCurto, Wade Nichols, Don Campbell, Dr. Dale Weber 2
CATTLE GRAZING AND RIPARIAN ZONES
Dr. William C. Krueger 11
EVALUATION OF MEADOWFOAM MEAL AS A PROTEIN SUPPLEMENT FOR BEEF CATTLE
Dr. Peter R. Cheeke 14
BREEDING LIVESTOCK FOR SURVIVAL POTENTIAL - IS IT ON?
Dr. William D. Hohenboken 18
FACTORS AFFECTING BULL FERTILITY
Dr. A. R. Menino, Jr., Dr. Frederick T. Stormshak 25
APPENDIX
Effects of Energy Level and Frame Size on Lifetime Steer Performance
Tom Hill, Roger Miller, and Dr. Dale Weber
The Inheritance of Active and Passive Immune Mechanisms in Cattle and Sheep
Dr. William Hohenboken, Lindsay Norman, Priscilla Berggren-Thomas,
Noelle Muggli
Predicting Bull Fertility from Flow Cytometric Evaluation of Semen Samples
Brenda Ballachey, Don Evenson, Dr. William Hohenboken
Genetic and Management Alternatives for Costal Pacific Northwestern
Beef Cattle Production
Dr. William Hohenboken
Beef Cattle Herd Age Structures and the Inheritance of Longevity Traits
Dr. William Hohenboken, Deb Schons, Hajime Tanida
Selenium - Safety, Bio-availability and Transfer from Cows to Calves
Don Campbell, Dr. John Maas, Roger Miller, Dr. Dale Weber
Comparison of Wheat with Two Commonly Used Grains in a Finishing Ration
Wade Nichols, Dr. Dale Weber
Regulation of Corpus Luteum Function
Dr. Fred Stormshak
Embryo Physiology
Dr. Fred Menino
Interaction of Diet and Hormones in Controlling the Postpartum Period
of Beef Cows
Dr. Fred Stormshak, Dr. Harley Turner, Dr. Martin Vavra
24th Annual Beef Cattle Day
Saturday, May 16, 1987
109 Withycombe Hall - Oregon State University, Corvallis, Oregon
9:30 A.M. 10:00
10:15
11:00
11:30
Registration, $15.00 per person
Includes lunch and copy of
proceedings.
12:00 Noon
LUNCH
OSU Clark Meat Lab
Coffee and donuts.
1:15 P.M.
Welcome
Dr. Lloyd Swanson,
Acting Department Head
Department of Animal Science
Cows and Cricks
- Dr. William Krueger
Department Head
Rangeland Resources
1:45
Consumers Still Like Beef
- Margaret Lewis, R.D.
Nutrition Specialist
Extension Home Economics
Using Meadowfoam Meal
- Dr. Peter Cheeke
Professor
Department of Animal Science
2:05
Breeding Cows for Survival
- Dr. William Hohenboken
Professor
Department of Animal Science
2:30
Visit Soap Creek Ranch
Purebred Herd
Crossbred Cow Herd
Testing Bull Libido
Responding to Hormone and
Antibiotic Concerns From
Consumers
- Dr. Steve Davis
Acting Director
OSU Ag Experiment Stations
Ionophores - The Other Feed
Additive
- Dr. Dale Weber
Associate Professor
Department of Animal Science
1
USE OF IONOPHORES IN COMMERCIAL BEEF CATTLE PRODUTTION
2
Timothy DelCurto , Wade Nichols Don Campbell
and Dale W. Weber
Department of Animal Science, Oregon State University
INTRODUCTION:
Ruminant animals are unique in respect to their
symbiotic relationships with digestive bacteria and protozoa.
The host animal and rumen microbe interaction allows for
utilization of low quality feedstuffs not suitable for humans
and nonruminant animals. While fermentation in the rumen is
a definite advantage to the host animal, it has been the
desire of ruminant nutrition researchers to manipulate rumen
metabolism. It has only been within the past ten years that
chemical agents have been utilized that offer significant
potential for manipulation of rumen function. Among those
chemical agents are ionophores,
antibiotic drugs, that
favorably affect the rumen microbial populations. The
results are increased average daily gain (ADG) and more
efficient feed utilization.
The goal of this paper is to define ionophores, to state
how they benefit the animal and how they can be applied to
commercial beef cattle production. Oregon State University
has been active in ionophore research and a brief summary of
the research completed will be presented.
1
2
Graduate students
Former graduate student
3
Associate Professor
Ionophores
Ionophores are compounds that facilitate the transport
of ions across biological membranes. When fed to a ruminant
animal in the proper amounts, ionophores inhibit the survival
of many rumen microbes while benefiting other substrate
limited microbes. As a result, ionophores alter the rumen
microbial population and indirectly change rumen fermen
tation. The change in rumen fermentation is the primary
factor leading to increased ADG and feed efficiency. The
most common ionophores fed are:
Trade Name
Monensin-Sodium
Lasalocid-Sodium
Rumens in
Bovatec
Produced By
Eli Lilly and Co.
Hoffmann-La Roche Inc.
Others: Salinomycin, Narasin, Avoparcin.
2
Changes in Rumen Fermentation
One of the most often cited benefits of ionophores is
the change in levels of volatile fatty acids (VFA), which are
utilized for energy. In non-ruminants, glucose is the
primary
In ruminant
energy form that is metabolized.
animals, VFA's, specifically acetate, propionate and butyrate,
are
the
products of microbial digestion.
end
Ionophores have been shown to increase the amount of
propionate at the expense of acetate and butyrate (Dinius et
al., 1976; Bartley et al., 1979; Thonney et al., 1981). This
is important to the animal because propionate is more
efficiently utilized for energy synthesis by the ruminant
than either acetate or butyrate (Hungate, 1966; Chalupa,
1977).
Ionophores have also been shown to decrease ruminal
protein digestion and ammonia (Fuller and Johnson, 1981;
Darden et al., 1985). This allows high quality feeds to
escape degradation in the rumen and pass to the abomasum and
small intestine where they are more efficiently utilized.
Another change in rumen fermentation that is a benefit
to the animal is the decrease in methane production.
Depending on the feed type, eructation of methane gas
represents 4-8% of the gross energy of the diet. Ionophores
have been shown to decrease methane production by as much as
30% (Bartley et al., 1979; Thornton and Owens, 1981), which
enables the host animal to utilize energy more efficiently.
There are many other ionophore induced changes in rumen
fermentation that benefit the ruminant animal. With high
concentrate (grain/energy) rations, ionophores increase
ruminal pH and decrease lactic acid production (Nagaraja et
al., 1983). This can be directly correlated to the reduction
of lactic acidosis and grain bloat in feedlot rations. With
cattle grazing pastures, ionophores have been shown to
increase forage intake (Pond and Ellis, 1981) yet decrease
the occurrence of grass/legume bloat. Ionophores have also
been sited for the decreased occurrence of acute bovine
pasture
pulmonary edema or emphysema with
cattle
on
(Potchoiba et al., 1982; Nocerni et al., 1985).
To the producer/feeder of beef cattle the important
features of ionophores are increased ADG, improved feed
efficiency and health of the herd. If used properly,
ionophores can economically aid the producer in attaining
these management goals.
RESEARCH TRIALS AT OREGON STATE UNIVERSITY:
Oregon State University has been active in conducting
ionophore research for five years, and the emphasis has been
the incorporation of ionophores into commercial beef cattle
production schemes. Following is a brief summary of five
research trials that have been completed:
3
Trial 1-Graded Levels of Supplementation of Lasalocid. (1982)
The goal of this trial was to evaluate the performance
of cattle with graded levels of ionophores. Sixty yearling
steers were allotted to three treatments: 0, 50 and 100 mg
lasalocid-sodium per head per day. The lasalocid-sodium was
mixed in a finely ground grain carrier and hand-fed in bunks
at two pounds per head per day. At the time of this trial,
the most beneficial amount of lasalocid needed to yield
maximum weight gain response was not firmly established. The
palatability of high levels of lasalocid in small amounts of
carrier grain was also unclear.
Using the initial and final "shrunken" weights, the ADG
for 0 mg, 50 mg and 100 mg treatments were 1.07, 1.12 and
1.25 pounds per head per day, respectively. While there was
a numerical response with both lasalocid-sodium levels, only
the 100 mg treatment level was found to be statistically
significant. Lasalocid fed in the finely ground grain car
rier was readily consumed, indicating that the grain was an
effective carrier.
In this trial, lasalocid caused a significant weight
gain response when fed at 100 mg per head per day. Other
research, however, established 200 mg per head per day as the
optimum level of supplementation.
Trial 2 - Effect of Lasalocid on Fall Calving Beef Cows.
(October, 1983 to April, 1984)
The purpose of this trial was to test the efficacy of
feeding lasalocid to lactating beef cows. The following
parameters were measured:
-
cow weight changes and body condition,
twelve hour milk production,
percent milk fat and percent milk protein,
actual calf weights and 205-day adjusted weaning weights,
average days open (parturition to conception).
Lasalocid was fed in a finely ground grain carrier at 0 and
200 mg per head per day.
Results of this trial indicated that lasalocid had no
significant effect on any of the measured parameters. While
no apparent advantage was found by feeding lasalocid during
this trial, dry matter intake could have been reduced.
Likewise, no detrimental effects were observed in long term
feeding of lasalocid to fall-calving beef cows.
Trial 3 - Supplementation of Lasalocid Via a Mineral Carrier.
(May, 1984, to August, 1984)
This trial was conducted to evaluate the efficacy of
feeding lasalocid in salt-mineral carrier. Salt-mineral
supplements are often used in commercial cattle operations.
4
The use of them as carriers would add little if any
additional cost to the producer.
Forty-two head of stocker cattle were allotted by weight
and sex to two treatments. The control groups were fed
Moorman's Range A mineral. The treated groups were fed the
same mineral formulation; however, it also contained 1440
grams lasalocid per ton of mineral (1.588 g lasalocid/kg
mineral).
Throughout the course of this 84-day trial, consumption
of the mineral was measured at 14-day intervals. Consumption
of the control mineral was greater (P < .05) than that of the
mineral containing lasala cid (Table 1).
Table 1. Consumption of Medicated and Non-Medicated Mineral
Salt (kg).
Lasalocid
Trial Status Steer
Day 1-28
.15
Day 29-56
.10
Day 57-84 07
Day 0-84
11
Lasalocid
Control
Control
Heifer
Steer
29
.13
.12
18
Heifer
12
.04
.05
07
.17
20
.11
16
- consumption of Bovatic mineral = .09 kg/hd/day
- consumption of Control mineral = .17 kg/hd/day
The variable consumption pattern of the mineral treated
with lasalocid can possibly be correlated with the lack of
weight gain response (see Table 2).
Table 2. Average Daily Gain (kg) of Stocker
Cattle Consuming Medicated and
Non-Medicated Mineral.
Treatment
Sex
Lasalocid
Total
Heifers
Steers
Total
Heifers
Steers
Control
5
ADG
1.22
1.11
1.28
1.17
1.06
1.23
While a slight numerical increase in ADG was observed in the
lasalocid-treated groups, this was not significant.
This
research trial should not be interpreted as
discouraging the use of lasalocid in mineral supplements.
Instead, some manipulation of salt content and other
palatability factors should be considered to ensure stable
consumption over time. Muller et al. (1986) showed that by
altering the salt content of supplements containing monensin,
a 10% increase in ADG resulted. If consumption can be
increased and variabil ity decreased, significant weight gain
responses can be obtained.
Trial 4 - Supplementation with Lasalocid Three Times Weekly
to Stocker Cattle on Pasture. (April, 1985, to
August, 1985)
Feeding lasalocid three times weekly is a practical
approach to com mercial stocker cattle production.
Obviously, the goal of the commercial producer is to maximize
profits and minimize costs. Feeding a grain supplement
everyday to stocker cattle grazing on pasture can be labor
intensive and costly. If the cost of supplementation is
greater than the benefit derived, motivation for the usage of
lasalocid-grain carrier sup plements is lost. If the amount
of supplement fed and the frequency of feeding are decreased,
the benefit of a lasalocid-grain carrier is increased.
Seventy-two head of yearling steers were allotted by
weight to four treatments. Treaments consisted of: (1) .45
kg ground corn per head per day; (2) .45 kg ground corn per
head three times weekly on Monday, Wednesday and Friday; (3)
.45 kg ground corn with 200 mg lasalocid per head per day;
(4) .45 kg ground corn with 467 mg lasalocid per head three
times weekly. Both lasalocid treatment groups received the
same weekly allowance of lasalocid (1400 mg lasalocid).
Lasalocid fed on an everyday basis increased (P < .01)
ADG over controls by 11 percent (see Table 3). Lasalocid fed
on an alternate day basis caused a numerical increase;
however, this was not significant.
Table 3. ADG of Steers Supplemented with
Lasalocid Everyday Versus Three
Times Weekly.
Treatment
ADG (lbs)
Control everyday
Control 3X weekly
Lasalocid everyday
Lasalocid 3X weekly
2.47
2.35**
2.75
2.44
Least significant difference (LSD) @ .01
alpha level.
= P < .01.
6
Trial 5 - Intake of Liquid Supplements and Protein Blocks
Containing Lasalocid (Bovatec) by Stocker Cattle on
Pasture.
The economical gains associated with feeding lasalocid
have been well documented. Cattle improve both in feed
efficiency and rate of gain when lasalocid is supplemented on
a daily basis. The supplementation of feedlot cattle vs.
stocker cattle is comparatively simple when looking at labor
and miscellaneous costs involved. If there is no practical
and economical way in which to supplement stocker cattle,
then the producer loses the potential benefit. The problem
is how to provide lasalocid on a daily basis by a method that
is both practical and economically fea Bible. One solution
to the problem is to provide the necessary require ment in a
form of supplementation that is well proven and efficient.
Seventy-two head of cross-bred heifers, born in the
spring of 1986 at the Soap Creek Ranch at Oregon State
University, were stratified by weight and allotted to 9
groups. The 9 groups were then randomly assigned a pen
number followed by a random assignment to 1 of 3 different
treatments. The treatments consisted of: 1.) Liquid
supplement acontaining laslaocid and labeled SEXP #1 at Berry
Creek Ranch , 2.) Liquid supplement containing lasalocid and
labeled SSEX #3 at Berry Creek Ranch , c 3.) Protein blocks
containing lasalocid at Soap Creek Ranch C .
Treatments were
replicated 3 times with 8 heifers per replication. Weekly
consumption was recorded as well as heifer weights at the
begin ning, middle, and end of the trial.
The optimum levels of consumption, as determined by the
Food and Drug Administration (FDA) in their acceptable range
of 60-200 mg/head/day of active ingredient (lasalocid sodium)
were determined to be: Treatments 1 and 2, .75-2.00
lbs/head/day of carrier; Treatment 3, .5-1.00 lbs/head/day of
carrier. Treatments 1 and 2 fell within this optimum level
on an average during the 98 day trial. Treatment 3
consumption extended above the optimum range on an average
for the 98-day trial (see table 4).
This trial indicates that consumption at an optimum
level was achieved via the liquid carrier. These cattle
consumed sufficient carrier to receive the additional
benefits of the ionophore.
The protein block treatment consumption exceeded the FDA
approved levels. Although the cattle may benefit from the
adition of lasalocid, consumption needs to be decreased in
order to comply with FDA regulations and to minimize costs to
producers.
Research is currently being conducted at other
universities to verify consumption rates of these same
supplements. These carriers should be approved in the near
future for stocker cattle on pasture.
7
Table 4.
Consumption Data of Stocker Cattle Consuming
Pasture Supplements.
Treatment Replicate
b
SSEX #3 1
SSEX #3
2
SSEX #3
3
SEXP #l a1
SEXP #1
2
SEXP #1
3
Prot. Blks. c1
Prot. Blks.
2
Prot. Blks.
3
Total
lbs.
Consumed
Average Daily Gain
Average
Daily
final
Consumption
60 days
98 days
1135
684
1134
586
1275
1203
1191
912
1077
1.45
.87
1.45
.75
1.63
1.53
1.52
1.16
1.37
.93
.66
1.52
.85
1.17
1.25
.83
.60
1.02
1.57
.95
2.15
1.45
1.71
1.76
1.52
1.25
1.74
2953
3064
6017
3180
1.26
1.30
1.28
1.35
1.04
1.09
1.06
.82
1.56
1.64
1.60
1.50
TOTALS
SSEX #3
SEXP #1
Combined total
Prot. Blks.
a
Hoffmann-LaRoche Generic Liquid Feed Supplement #3.
Hoffmann-LaRoche Generic Liquid Feed Supplement #1.
c Hubbard Milling Co., Mankato, MN. Crystalyx Blocks.
SUMMARY
The supplementation of stocker cattle on pasture can be
economically advantageous in certain situations. The
addition of lasalocid to this supplementation can improve
feed efficiency and rate of gain when con sumed at the
recommended daily level.
The supplementation of ionophores to cattle on pasture
or range conditions is still an active area of research. The
research at Oregon State University has indicated that
feeding lasalocid in a hand-fed carrier, in a liquid
supplement or in protein blocks is a practical means of
supplementation. Supplementing lasalocid in a salt-mineral
carrier yields less than encouraging results and alternate
day feeding does not appear practical at this point.
Research
with
(rumensin) has been more
monensin
successful in supplementing to cattle via a mineral carrier
8
and on an alternate day basis. With the added advantage of
manipulating salt content of the mineral, Muller et al.
(1986) have reported a 10 percent increase in average daily
gains. Monensin fed on an alternate day basis has also been
reported to yield the same weight gain response as monensin
fed on an everyday basis (Muller et al., 1986).
At the present time, Bovatec is approved for cattle on
pasture at the rate of 60-200 mg/hd/day. For confined
cattle, the approval for Bovatec is 10-30 g/ton of complete
feed, which should provide from 100-360 mg/hd/day. If
Bovatec is contained in a purchased supplement for feedlot
cattle, it should be fed according to the manufacturer's
direc tions so that the appropriate consumption of lasalocid
will be achieved.
Bovatec is approved for cattle on pasture to improve
rate of gain, and it may be hand-fed in a grain carrier. It
may also be provided free choice in the form of loose mineral
supplements, blocks or liquid supple ments. However, feed
manufacturers are required to demonstrate approved Bovatec
consumption in the free choice supplements in order to meet
FDA requirements. To date, Bovatec has been approved in a
block formulation and for a free choice mineral supplement
for specific feed manufacturers.
REFERENCES
Bartley, E.E., E.L. Herod, R.M. Bechtle, D.A. Sapienza,
B.E.
Brent and A.
Davidovich.
1979.
Effect of
monensin or lasalocid, with and without niacin or
amicloral, on rumen fermentation and feed efficiency.
J.
Anim.
Sci.
49:1066.
Chalupa, W. 1977. Manipulating rumen function. J. Anim.
Sci. 45:585.
Darden, D.E., N.R. Merchen, L.L. Berger and G.C. Fahey.
1985. Effects of avoparcin, lasalocid and monensin on
sites of nutrient digestion in beef steers. Nutr. Rep.
Int. 31:979.
Dinius, D.A., M.E. Simpson and P.B. Marsh. 1976. Effect of
monensin fed with forage on digestion and the ruminal
ecosystem of steers. J. Anim. Sci. 42:229.
Fuller, J.R. and D.E. Johnson. 1981. Monensin and lasalocid
effects on fermentation in vitro. J. Anim. Sci.
53:1574.
Hungate, R.E. 1966. The rumen and its microbes. Academic
Press, Inc., New York.
9
Muller, R.D., E.L. Potter, M.I. Wray, L.F. Richardson and
H.P. Grueter. 1986. Administration of monensin in
self-fed
(salt-limiting) dry supplements or on an
alternate-day feeding schedule. J. Anim. Sci. 62:593.
Nagaraja, T.G., T.B. Avery, E.E. Bartley, S.K. Roof and
A.D. Dayton. 1982. Effect of lasalocid, monensin or
thiopectin on lactic acidosis in cattle. J. Anim.
Sci.
54:649.
Nocerini, M.R., D.C. Honeyfield, J.R. Carlson and R.G.
Breeze. 1985. Reduction of 3-methylindole production
and prevention of acute bovine pulmonary edema and
emphysema with lasalocid. J. Anim. Sci. 60:232.
Pond, K.P. and W.C. Ellis. 1981. Effect of monensin of
fecal output and voluntary intake of grazed coastal
bermuda grass. Texas Agric. Exp. Stat. Pub. No. 31.
Potchoiba, M.J., M.R. Nocerini, J.R. Carlson and R.G.
Breeze. 1984. Effect of energy or protein supplements
containing monensin on ruminal 3-methylindole formation
in pastured cattle. Amer. J. Vet. Res. 45:1389.
Thonney, M.L., E.K. Heide, D.J. Duhaime, R.J. Hand and
D.J. Perosio. 1981. Growth, feed efficiency and
metabolite concentrations of cattle fed high forage
diets with lasalocid or monensin supplements. J. Anim.
Sci. 52:427.
Thornton,
J.H.
and
F.N.
1981.
Owens.
Monensin
supplementations and in-vivo methane production
by
steers. J. Anim. Sci. 52:628.
10
Cattle Grazing and Riparian Zones
William C. Krueger
Department of Rangeland Resources
Oregon State University
Corvallis, OR 97331
Cattle grazing on rangelands involves a multitude of management decisions
directed towards immediate business success, sustainability of the
enterprise and maintenance of environmental quality. Riparian zones (the
land adjacent to streams, rivers, lakes, etc.) figure prominently in each
of these decision making areas for reasons of their high productivity and
forage quality. They often provide the bulk of nutrients actually
consumed by range cattle and because of their high productivity, they are
also focal points for production of wildlife. Riparian zones are the
conduit to deliver water to lakes and reservoirs so water quality becomes
a concern of down stream users. In many ways, the riparian zone reflects
the total condition of the watershed and is sometimes used as a barometer
of the overall health of the land. Regardless of one's specific interest
in riparian zones, we are going to continually pay special attention to
them in making management decisions. The best decisions are made from a
factual basis, so one understands the potential benefits or losses that
might result from a change in management. This report summarizes a
portion of the research done over the last dozen years on forested ranges
of northeastern Oregon.
A discussion of riparian zones needs to consider that these areas are part
of a larger environmental system and they do not function independently.
Likewise, they are typically grazed as a part of larger pastures and the
use made by cattle is determined by a complex of management actions,
cattle behavior, and environmental characteristics. In large pastures,
900 to 13,000 acres, cattle segregated into small groups and established
home ranges where they spent all of their time in the pasture. A home
range always included a water source but only included a riparian zone
about half of the time. Cattle returned to water at least once each day.
When riparian zones were present in the home range, they were highly
preferred. Preference was generally highest for riparian zones and
decreased in order of grasslands, clearcuts, other logged areas, and was
lower for areas unlogged in recent years. As the season progressed, the
relative preference for different vegetation types changed depending on
the forage resources.
Riparian zones were preferred foraging areas. In the Blue and Wallowa
Mountains, where these studies were carried out, the riparian zone
comprised 2-3% of the pastures and produced more than 20% of the total
forage in the pastures. With the typical utilization of about 75% of the
forage produced, the riparian zones provided about 80% of the forage
consumed by cattle. So with current management, an acre of riparian zone
is worth about 200 times as much as an acre of uplands in terms of cattle
forage dependency.
11
Cattle typically entered a pasture in a riparian zone and then dispersed.
It would take 2-3 weeks for the cattle to settle into these home ranges.
While forage on riparian zones was used faster under deferred-rotation
grazing systems than continuous grazing systems, the actual utilization of
each riparian zone ended about the same irrespective of early, late or
continuous grazing. The time cattle spent in riparian zones was highest
late in the grazing season. Early summer grazing facilitated dispersal of
cattle and reduced occupancy of riparian zones by about half. Studies of
microclimate and probable cattle heat stress indicated there was no clear
superiority of riparian zones over the uplands.
Observations of riparian zones heavily grazed by cattle indicated they
were vegetatively stable, usually dominated by Kentucky bluegrass. No
regrowth occurred when pastures were grazed through July. However, with
changes in grazing, the riparian zones could increase or decrease shrub
cover and other vegetational characteristics.
Impacts of cattle grazing on vegetation and wildlife of riparian zones
have also been evaluated. Our classification of the plant communities of
Meadow Creek on the Starkey Experimental Range indicated there were 44
different plant communities in the 110 acres of riparian zone. In fact,
the streambed itself occupied more area than any single vegetation type.
On Catherine Creek on the Hall Ranch research area of the Agricultural
Experiment Station, we found 60 plant communities in a riparian zone of
about 400 acres. This area had 265 plant species present.
Measurement of impacts on these areas is necessarily complicated. In
general, grazing tends to favor grasses that are often replaced by sedges
and forbs as grazing is eliminated. Use of browse is closely related to
availability of green grass. As green grass is used, utilization of
browse increases. Stability of streambanks is also affected by grazing.
It appears that there may be a threshold that must be exceeded before
measurable impacts of grazing are found.
On Catherine Creek, with a fall grazing program, stocking at a rate of one
cow and calf per day per linear yard of stream bank; bank loss was about
6" per year compared to a loss of about 2" per year with no grazing.
Prior to this study, the area was stocked summer and fall at a rate of
about one cow and calf per 2 linear yards of stream. Our data from this
period is limited, but it suggested that stocking at this rate was about
the same as no grazing. Dr. John Buckhouse has conducted a more thorough
study of streambank loss and grazing on Meadow Creek. He has found that
the impact of cattle on streambanks is secondary to impacts of natural
events that ultimately determine erosion in that system.
We have measured responses of birds and small mammals, mice, etc. to fall
grazing on Catherine Creek. Birds nest before the area is grazed so the
habitat is good for them and small mammals though reduced by grazing fully
recover in spring. The fall grazing approach seems to be neutral to
wildlife.
12
Summary
Cattle grazing does influence the vegetation and soils in riparian zones.
This influence can be positive or negative depending on the specific
methods of grazing and objectives of the landowner. Most riparian zones
can probably be grazed by cattle successfully. It is important to first
decide the objectives of management on the site, second decide the
probable grazing program to integrate uplands and riparian zones to
achieve the results you want, and third implement a system to evaluate
your success in reaching objectives and to adjust grazing, if necessary.
When the whole package is put together, the needs to graze a watershed for
livestock production, wildlife production, water production, and other
values can be integrated so that all values are achieved.
13
EVALUATION OF MEADOWFOAM MEAL AS A PROTEIN SUPPLEMENT FOR
BEEF CATTLE
P.R. Cheeke
Dept. of Animal Science
Oregon State University
Meadowfoam (Limnanthes alba) is a winter annual native
to the Pacific coastal region of North America. It is being
developed as an oilseed crop for production on poorly
drained land, with commercial production initiated in Oregon
in 1984. The meal remaining after oil extraction contains
21% crude protein, 27% acid detergent fiber and 4.2% total
glucosinolates (Throckmorton et al., 1982). It has been
evaluated as a feed for rabbits and chickens (Throckmorton
et al., 1981), sheep (Throckmorton et al., 1982) and goats
(White and Cheeke, 1983). These studies have shown adverse
effects in non-ruminant animals, caused by glucosinolates in
the meal, but satisfactory performance of lambs fed raw meadowfoam meal (MFM) was observed (Throckmorton et al., 1982).
The objective of this experiment was to evaluate MFM as
a feedstuff for beef cattle, for which results with MFM have
not previously been reported. Raw MFM was incorporated into
pelleted diets at levels of 0, 12.5% and 25% (Table 1). The
diets were formulated to be isonitrogenous. Two pens of
crossbred (Hereford x Angus) steers of about 241 kg initial
weight (range 184-326 kg) were assigned to each diet, with
seven steers per pen. Animals were allocated to pens to
give a similar average initial weight for each pen. They
were fed the pelleted diets to appetite for a period of 84
d, with 1.6 kg grass hay (6.8% crude protein) per head fed
daily. Feed consumption per pen was recorded daily, and
individual body weights were measured every 14 d. Weight
gans were analyzed by analysis of variance, with treatment
means compared by the Student-Newman-Keul test.
14
Table 1.
Percentage composition of diets.
Meadowfoam meal (MEM)
Cottonseed meal
Barley
Alfalfa
Grass hay
Molasses
Limestone
+
Trace-mineralized salt
11
35
10
37
6
0.5
0.5
12.5
4.6
35
10
30.9
6
0.5
0.5
25
35
10
23
6
0.5
0.5
Analyzed composition
Dry matter (%)
++
Crude protein (%)
Acid detergent fiber
++
90.2
11.8
19.5
(%)++
89.3
12.9
19.9
90.1
14.1
19.3
Throckmorton et al. (1982).
Dry matter basis.
The results (Table 2) indicate that raw MFM was a
satisfactory feedstuff for growing beef cattle. The ADG was
depressed (P < 0.05) during the first 4 wk period with the
diet with 25% MFM. This was probably an initial aversion to
the glucosinolates, which adversely affect palatability
(Cheeke and Shull, 1985). However, this initial reduction
in gain, which was mainly associated with three steers in
one pen which lost weight over the first 27 d, was compensated for by increased gains in the remainder of the trial,
so that over the entire experimental period, there were no
differences in performance among the treatment groups.
15
Table 2. Average daily gains and feed/gain for beef cattle
fed various levels of meadowfoam meal.
Level of MFM
0
12.5%
25%
Average daily
gain (kg)
0-27 d
28-55 d
56-84 d
0-84 d
Feed/gain+
1-27 d 28-55 d
56-84 d
0-84 d
0.568 + 0.289
1.278 T 0.288
1.411 T 0.323
1.063 T 0.194
a
ab 0.316 + 0.318 b
0.469 + 154
1.277 T 0.298 1.314 + 0.334
1.594 T 0.300 1.465 T 0.203
1.092 T 0.162 1.012 T 0.189
8.42
4.83
4.54 5.19
6.95
4.83
5.13
5.33
12.50
4.70
4.94
5.60
Calculated using intake of pelleted diet (as-is basis)
only; does not include hay.
a different than b (P < 0.05).
This study indicates that raw MFM is an acceptable feedstuff
for growing cattle at up to 25% of the diet. Because of its
glucosinolate content, and the evidence that goiter may be
induced in offspring of goats fed raw MFM (White and
Cheeke, 1983), this product should not be fed to pregnant
beef cows until its goitrogenic potential in cattle has been
fully assessed.
REFERENCES
Cheeke, P.R. and Shull, L.R. 1985. Natural toxicants in
feeds and poisonous plants. AVI Publishing Co.,
Westport, Conn.
Throckmorton, J.C., Cheeke, P.R., Patton, N.M., Arscott,
G.H. and Jolliff, G.D. 1981. Evaluation of meadowfoam
(Limnanthes alba) meal as a feedstuff for broiler
chickens and weanling rabbits. Can. J. Anim. Sci.
16
61:735-742.
Throckmorton, J.D., Cheeke, P.R., Church, D.C., Holtan, D.W.
and Jolliff, G.D. 1982. Evaluation of meadowfoam
(Limnanthes alba) meal as a feedstuff for sheep. Can.
J.
Anim. Sci. 62:513-520.
White, R.D. and Cheeke, P.R. 1983. Meadowfoam (Limnanthes
alba) meal as a feedstuff for dairy goats and toxicologic activity of the milk. Can. J. Anim. Sci.
63:391-398.
17
BREEDING LIVESTOCK FOR SURVIVAL POTENTIAL - IS IT ON?
William D. Hohenboken
Department of Animal Science
Oregon State University, Corvallis, OR 97331-6702
Cows must produce a respectable amount of milk to raise a respectable
calf; and both cows and bulls must have the genetic capacity to reproduce.
Growth rate and mature size also are important; because, after all, you are
paid for pounds of beef produced. Carcass quality is also economically
important, and attention must be paid to the present and future product
specifications of your customers. A variety of traits are competing for
attention in a selection program, and it is hard to know how much effort to
devote to each.
You can hardly dispute, however, that survival is the most important
economic characteristic of all. A calf with ideal genetic merit for
reproduction, milk yield, growth and carcass merit is worthless unless it
survives. This raises the question of whether, and if so how, genetic
selection should be applied to increasing survival potential of our livestock.
In this paper, I will first present general considerations and principles
relevant to selection for survival potential, illustrated with results from
some recent experiments. The paper will conclude with my own recommendations
of what breeders can do to enhance genetic merit of their stock for survival
potential and health.
General Considerations
Livestock producers, extension agents, veterinarians and animal
scientists take justifiable pride in our efforts to provide for the welfare
and health of our animals. We should not forget, though, that Mother Nature
has been in the animal health business a lot longer than we have. Cattle have
been domesticated for perhaps 8000 years and they have been under conscious
selection for economically important traits only for something over a century.
Cattle and their ancestors have been evolving, in response to the challenges
of their environment, for millions of years. They have developed behavioral,
physiological and immunological mechanisms for survival that are spectacularly
effective; otherwise they could not be here at all. So a first consideration
is to realize that Mother Nature has been working on the problem of animal
health for a very long time. We would be naive to expect to make wholesale
and dramatic changes in survival potential in the relatively few generations
of selection at our disposal.
A second consideration, though, is that in contemporary livestock
production, we have changed the rules. With domestication, private ownership
of land, provision of conserved forages and/or concentrates, pasture
fertilization, mineral supplementation, intensive grazing and countless other
technological and management changes, we are imposing upon our animals a
different and sometimes unhealthier environment than that experienced by their
distant ancestors. Granted, we are inclined to provide more adequately for
their nutritional needs, but this luxury may be provided to them at the
expense of greater crowding, with the consequence of greater parasite and
disease exposure. It could also be argued that selection for increased
18
production has placed greater physiological stress on our animals, increasing
their susceptibility to stress-related conditions and diseases. Milk fever,
for example, was less prevalent when dairy cows were producing only half the
milk they now produce. Because we have dramatically changed the production
potential and the environments in which livestock are expected to produce,
perhaps Mother Nature could use some help in fine tuning our livestock to the
demands generated by modern farming schemes.
A third consideration is that, whether we like it or not, there is
continued natural selection for increased survival and health. Dead calves
and lambs don't reproduce, so we cannot outlaw natural selection. As
examples, calves that are markedly heavier or lighter at birth than average
for a given herd are less likely to survive. The small calves may die from
weakness and starvation, the large ones from a difficult birth. The end
result is natural selection towards intermediate birth weights. Bulls and
cows that are more heavily parasitized than their contemporaries may
contribute fewer offspring to the next generation, and any genes they have
promoting susceptibility to parasites should decrease in frequency. Any
methodical selection we apply to survival potential will be superimposed upon
continued natural selection.
A fourth consideration is that disease resistance and survival potential
cannot be thought of as a simple, unified mechanism or trait. That is, an
animal will have a multitude of strategies to promote its survival and wellbeing. Some of the factors are physical in nature, a proper balance between
cow size and pelvic architecture with calf shape and birth weight, for
example. Others are behavioral, such as the ability of a cow to care for her
calf at birth and to choose a safe environment, defend against predators,
etc. Others are immunological (the ability to ward off a disease challenge)
or metabolic (the ability to detoxify harmful chemicals and to maintain body
chemistry within acceptable bounds). Some of these factors are likely to be
subject to improvement by selection, and others probably are not.
A fifth and final consideration is that past natural selection and
evolution have created a complex, interrelated system that works. Tampering,
by selection, with one aspect of the system may have the desired effect with
respect to that aspect of the system but may have undesirable side effects
elsewhere. For example, intense selection for growth rate in beef cattle has
caused dramatic changes in growth rates and in weights at all ages, as
expected. However, it has also created an imbalance between calf birth weight
and cow size, leading to increased incidence of dystocia, higher calf
mortality and poorer rebreeding performance in the dystocial cows. As another
well-documented but not unique example, a German scientist selected lines of
mice for increased and decreased levels of phagocytic activity of white blood
cells. (This is one of the body's most effective defenses against bacterial
disease challenges.) The upward selected mice were more resistant to
bacterial diseases, as expected, but they were more susceptible to certain
viral diseases and to cancer. The downward selected mice were opposite. The
greatest lifetime reproduction actually was achieved by the control line mice,
which were not selected for their phagocytic responses at all. Mother Nature
seems to have known best, at least with respect to that particular
immunological trait. The artificial selection upset a finely tuned balance
and resulted in a reduction in overall fitness.
19
Principles of Selection for Survival Potential
Three conditions are necessary before a trait will respond to breeder
selection. First the trait must be measurable. Second, it must be
variable. Finally, it must be heritable. When all these conditions are met,
and when we are not so unfortunate as to be working against the goals of
Mother Nature, then to "select the best and cull the rest" should bring about
the changes that we desire. Applying these principles to survival traits,
though, is a little more complicated than for something straightforward like
yearling weight. It will be useful to provide the following framework for our
thinking.
As illustrated in the first accompanying figure, cattle in any population
will differ in their overall susceptibility (towards the left) or resistance
(towards the right of the figure) to a particular disease. Some few animals
will be very highly resistant, some few highly susceptible, with most
somewhere near the average. Net resistance is determined partly by an
animal's genetic constitution with respect to susceptibility to the disease in
question and partly by the effects on susceptibility of the animal's past and
current environment. (A corollary to this observation is that two animals
could have the same resistance but for different reasons. One could have
"good" genes, a "poor" environment, the other vice versa.) For some diseases,
genetic differences in aspects of resistance could be relatively more
important than environmental differences (i.e., the resistance would be highly
heritable). For other diseases, environmental differences could be much
larger than genetic ones, in which case heritability would be low.
A disease challenge imposed on the herd is illustrated in the second
figure. Although it would not be true in practice, we will assume that every
calf gets an equal dose of the disease challenge. We can think of a threshold
(represented by the vertical line on the third figure) existing in overall
resistance, such that animals to the right of the threshold do not develop the
disease, animals that fall to the left do get sick, despite the equal
challenge. In genetic selection (see the fourth figure), we would try to
enhance average genetic merit for disease resistance, in essence to shift the
whole population to the right so that a smaller percentage of the herd falls
to the left or susceptible side of the threshold. Changes in management, a
more effective hygiene or vaccination program, for example, also are attempts
to shift the population to the right.
A problem, though, is that we are not operating on our own. The
bacterium or virus causing the disease is not likely to accept blandly this
assault to its well-being. It also has the potential for genetic change, and
as we select the cattle for greater resistance, the pathogen simultaneously
may undergo natural selection for greater virulence. Thus the threshold also
can shift, as illustrated in the last figure.
Is Selection For Survival Potential Futile?
This may seem a pretty discouraging scenario. After all, there are a lot
more bacteria of any one species than there are cattle, and they reproduce
much more rapidly. It would seem they could easily circumvent our efforts to
select against them and that selection for survival potential would therefore
be futile.
20
VARIATION IN DISEASE RESISTANCE
A DISEASE CHALLENGE
THE RESISTANCE THRESHOLD
A SHIFTED DISTRIBUTION
A SHIFTED THRESHOLD
22
There are at least three arguments against such a pessimistic conclusion.
First, in both plant and animal populations, selection for long-term
improvement in resistance to certain pathogenic diseases has, in some cases,
worked. In poultry, for example, selection for decreased mortality from
Marek's disease or avian leucosis has been effective, and much of the response
was . due to a gene at a blood group locus (somewhat akin to the A-B-0 blood
group system in humans). At Ohio State University, researchers have developed
a selection line of Targhee sheep with much enhanced resistance to footrot.
Longterm selection for twinning rate in a line of New Zealand Romney sheep
produced, as a correlated response to increased prolificacy, higher tolerance
in the sheep to the detrimental effects of intestinal roundworms. That is,
the selected sheep can harbor higher worm burdens without clinical signs of
parasitism and without reduced productivity. Finally, Australian researchers
have identified a Hereford x Shorthorn crossbred cow who is virtually immune
to tick infestation, under conditions which result in hundreds of ticks on
each of her contemporaries. Her resistance likely is genetic, because it is
shared by her offspring.
Second, we must remember that, when pathogens do evolve through natural
selection toward greater virulence, they are working for themselves, not
specifically against their cattle or sheep hosts. It is not the "goal" of the
worm or bacterium or virus to kill the beast. Rather it is its goal to eat,
drink, be merry, create lots of offspring and perpetuate its species. If it
overdoes it and kills the host, the party is over. The worms, bacteria and
viruses, if they thought about it, would be much happier with a tolerant host
than either a resistant one (one that does not allow them access) or a
susceptible one (one that provides them good temporary accommodation but then
dies). We, as well as our livestock, harbor millions of bacteria and virus of
many different sorts. Many of them are beneficial, even necessary, to our
welfare, some neither help nor hinder us, and some few are detrimental, i.e.
pathogenic. Perhaps selection can be directed successfully to a physical
constitution that will allow our animals to tolerate potentially harmful
invaders, rather than to resist them per se.
The third factor that argues against pessimism about selecting for
survival potential is that many instances of mortality or morbidity are not
caused by living organisms with the ability to "fight back" through natural
selection in their own populations. There are numerous examples - dystocia,
bloat, milk fever, and nutritional excesses or deficiencies. As one example,
sheep in Scotland have been selected successfully for increased copper
concentration in the blood. The selection was effective, and with the
increased blood copper, there was reduced lamb mortality from swayback - a
disease associated with copper deficiency - and from other causes as well.
And New Zealand researchers have found important genetic differences in dairy
and beef cattle in bloat incidence.
Recommendations
The jury is still out, and it may be out for some time before specific,
detailed selection programs for increased survival potential can be designed.
We are beginning to learn quite a lot about the heritability of some disease
resistance traits, but we know relatively little about the potential for
detrimental side effects of selection. Concerning immunological traits, there
is good evidence from research at OSU and elsewhere that animals differ
23
genetically in passive immunity (antibodies received by the newborn calf or
lamb from their mother's colostrum) and in active immunity as well (ability to
manufacture antibodies in response to a disease challenge or vaccination). We
have not yet, however, determined optimum levels of either passive or active
immune traits nor what particular balance among traits will lead to the best
survival potential. It also is uncertain whether disease resistance, disease
tolerance or some balance between the two is the more appropriate goal for
selection. They might be quite different traits, subject to separate genetic
control.
Despite the many unanswered questions, there are things that purebred
breeders and commercial farmers could do to enhance the genetic merit of their
animals for survival potential. I think of these as attempts to make Mother
Nature's job of natural selection easier and more efficient.
I would recommend that purebred breeders provide for their animals a
level of management that is consistent with sound and economical commercial
practice. Stated another way, stock for sale to commercial breeders should be
raised and selected under conditions that are more or less characteristic of
those in which the commercial descendants are expected to produce. Rams and
bulls that could not have survived a commercial challenge have no business
siring offspring for commercial conditions. The only way to determine if they
could have survived a commercial challenge is to provide the commercial
environment to them. I cannot advocate purebred breeders pampering their
stock, doing their best to nullify natural selection, then selling the result
to commercial customers.
For purebred and commercial breeders, I see a lot of merit in what New
Zealanders call "easy-care" livestock. They have defined as the production
objective, animals that calve or lamb unassisted, raise the offspring to
acceptable weaning weights and breed back to do the same thing next year, all
with minimal supervision, input and care from the farm operator. Until the
answers to some of the questions raised earlier are known, this philosophy and
strategy puts the onus of selection where it belongs, on Mother Nature. Any
animal that does not have the genetic potential to do the job does not
contribute genes to the next generation. This method may not be the fastest
means to achieve genetic change, but it is relatively foolproof and it cannot
very well backfire, that is, create more new problems that it solves. Some
cattle breeders are calling it "breeding from fault-free stock", that is, from
cows and bulls with unblemished records of reproduction and calf production.
The concept is the same.
In conclusion, I must issue a disclaimer. Principles, examples and
considerations given in this paper are based upon sound research and study.
But the recommendations are what I think as opposed to what I know. Selection
for survival potential is an area in which there is considerable uncertainty,
and some of my conclusions are subject to legitimate debate. Nevertheless, I
am convinced that by working with Mother Nature, the adaptability of livestock
to their particular production environments, their overall productivity and
their survival potential can be enhanced. I encourage you to get on with the
job.
24
Factors Affecting Bull Fertility
F. Stormshak and A.R. Menino, Jr.
Department of Animal Science
Oregon State University
Corvallis, OR 97331
Fertility of bulls is generally considered to be influenced
by several factors. Excluding disease or injury, the most
important are the following: 1) semen quality and(or)
quantity, 2) sex drive (libido) and mating ability and 3)
social interaction between animals. These factors will be
discussed individually.
Semen Traits
It is impossible to derive an accurate estimate of male
fertility by simply evaluating semen quality from a single
ejaculate. For example, Wiltbank et al. (1) examined the
relationships between sperm motility and morphology of bulls
and their subsequent breeding performance. These investigators found that average fertility of a group of bulls could
be predicted with some accuracy but the prediction of individual bull fertility was subject to error.
Bulls that are being considered for breeding purposes should
receive a breeding soundness examination (BSE) prior to
being tested for such traits as libido and serving capacity.
Scoring of breeding soundness should include a measure of
scrotal circumference (< 40%), sperm morphology (< 40%) and
sperm motility (< 20%). Using this scoring system and calculating pregnancy rates of bulls achieved during a trial
period with heifers subjected to estrous synchronization,
Chenoweth (2) found the correlations between pregnancy rate
and scrotal circumference, sperm motility and abnormal morphology to be significant. However, it should not be construed from such data that a BSE scoring system as proposed
can serve as a quantitative prediction of bull reproductive
performance. Instead, Chenoweth (2) recommended that the
BSE scores be employed to categorize bulls as being of
satisfactory, questionable or unsatisfactory prospective
breeders.
Libido and Mating Ability
The behaviors associated with libido and mating ability are
important features of a bull's reproductive potential. From
a physiologic standpoint, a bull may have seminal characteristics which are well within the accepted ranges; however,
if this individual has reduced libido and mating ability,
then he quickly approaches being unacceptable as a herd
sire. Alternatively, a bull with high libido may have poor
seminal characteristics, such as low sperm numbers, a high
25
proportion of abnormal sperm or a low percentage of motile
sperm. Chenoweth (2) has shown little relationship between
libido and measurement of seminal quality in bulls and
recommended that both factors be evaluated separately to
obtain an assessment of a bull's breeding potential.
Chenoweth (3) has further described a system for evaluating
sex drive among bulls using a libido test. In this test, a
bull is allowed to interact with a heifer in standing heat
in a small yard approximately 200 to 300 square meters in
size. Bulls are evaluated individually and are allowed to
interact with the heifer for exactly 5 min. All reactions
and movements of the bull are recorded on videotape for
observation and scoring at a later time. Bulls are assigned
a score or grade from a scoring system which has 11 ranks or
levels. The ranks start at 0, where the bull shows no
sexual interest, and end at 10, where the bull services the
heifer twice followed by sexual interest in the form of
mounts, attempted mounts or further services. Bulls are
tested twice in this libido test and the lower score is
discarded. Chenoweth (3) has also described a test to
evaluate mating ability among bulls. Mating ability is
scored using a system that has four grades ranging from 1,
in which the bull served the female satisfactorily, to 4,in
which the bull failed to show any evidence of mating ability. Systems for scoring libido and mating ability in bulls
do have merit as evidenced by a study utilizing 56 2-yearold bulls which were evaluated for libido prior to being
pastured with females. The correlation between libido score
among these bulls and pregnancy rate among the exposed
females was 0.32 and was higher than the correlation coefficient between semen quality score and pregnancy rate (0.13).
Hence, scores of libido and mating ability are valuable measurements of sexual behavior and yield important information
about a bull's breeding potential.
Social Ranking Among Bulls
It is common knowledge by all who have practical experience
with cattle that within a group of bulls there is a hierarchy of social dominance. Data of Osterhoff (as cited by
Blockey, 4) demonstrated that the oldest or second oldest
bull in the group sired 60% or more of the calves each year,
while the youngest bull sired 15% or fewer.
When in estrus, cows form a group called a sexually active
group and spend a rather large amount of time in this group.
Blockey (5) found that heifers spent 97% of the time they
were in estrus in the sexually-active group. Further,
dominant bulls spent an average of 91% of their time in or
near (within 20 m) the sexually active group while subordinate bulls spent only 53% of their time in or near it.
Blockey (5) also found that pregnancy rate of heifers mated
to a group of 2-year-old bulls exceeded that of heifers
mated to a mixed-age group of 2-year-old and older bulls.
26
In the mixed-age group, the older bulls were apparently
dominant over the 2-year-old bulls and, through this dominance, the older bulls were able to nullify the superior
mating performance of the younger bulls. Thus it can be
seen that social dominance can markedly affect reproductive
performance of bulls.
References
1.
Ingalls. 1965.
Wiltbank, J.N., W.W. Rowden and J.E.
University of Nebraska Research Bull. No. 224.
2.
Chenoweth, P.J. 1978. New and Not-So-New Concepts in
Bull Evaluation and Management. Proc. 11th Annu.
Convention Amer. Assoc. Bovine Practitioners, Baltimore,
MD.
3.
Chenoweth, P.J. 1980. Libido and mating ability in
bulls. In: Current Therapy in Theriogenology. pp. 342344.
4.
Blockey, M.A. de B. 1975. Studies on the social and
sexual behaviour of bulls. Ph.D. Thesis, Univ. of
Melbourne, Victoria.
5.
Blockey, M.A. de B. 1979. Observations of group mating
of bulls at pasture. Appl. Anim. Ethol. 5:15-34.
27
APPENDIX
NOTE: The Animal Science staff at Oregon State University feels that
research in the area of beef should address problems of the industry.
We recognize that many of the answers to these questions are only
to be found at the cellular levels. Often this type of research
is not highly visable or results may take some time to get direct
application.
Given this background we are taking the following method to supply
you with information on current research or research programs being
conducted at OSU. The following paragraphs are a brief outline
of such trials by research faculty members. As you might know
many of the projects are being conducted by our graduate students.
If you want further information or want to pursue any of the work
not represented at this year's OSU Beef Day, please feel free to
contact the OSU faculty member or one of the graduate students.
Effects of Energy Level and Frame Size on
Lifetime Steer Performance
by Tom Hill, Roger Miller and Dale Weber
Retained ownership is a viable option for many cattlemen. Oregon State
University is currently evaluating four management systems that producers who
retain ownership of their cattle through the feedlot might want to consider.
The four management systems under evaluation are: (1) creep feeding, then
weaning to a high energy finishing ration; (2) no creep feeding and then
weaning to a high energy finishing ration; (3) creep feeding, and then weaning
to a growing ration followed by 100 days on a finishing ration; (4) no creep
feeding and then weaning to a growing ration followed by 100 days on a
finishing ration.
The effects of these four treatments on large and small frame cattle are
being evaluated. Data that are being analyzed include: growth rate, feed
efficiency, days on feed, carcass quality, carcass yield grade and endogenous
growth hormone levels. The questions being addressed are that large frame
cattle can be produced more economically in an accelerated program because of
reduced interest, labor and feedlot costs. Also, younger cattle require less
marbling and fat to produce a high quality product. Data collection will be
completed in the fall of 1987.
THE INHERITANCE OF ACTIVE AND PASSIVE IMMUNE MECHANISMS
IN CATTLE AND SHEEP
William D. Hohenboken, with graduate students Lindsay Norman,
Priscilla Berggren-Thomas and Noelle Muggli
Department of Animal Science
A series of experiments, all completed, examined various aspects of the
inheritance of immune traits in ruminants. In the first experiment, it was
shown that a calf's breed did affect its ability to acquire colostral
antibodies from its mother, as did the mother's breed and various
environmental effects. That study also suggested a moderate to high
heritability of calf colostral antibody level. Our next experiments were done
in cooperation with the U.S. Meat Animal Research Center in Nebraska. Calves
from Hereford lines selected for weaning or yearling weight had lower
colostral immunoglobulin levels than calves from an unselected control
population, but heritability of immunoglobulin level was near zero. There was
evidence, though, that cows differed genetically in their ability to transmit
antibodies to their calves. The same calves were then tested for their immune
response to IBR vaccine. There were some technical difficulties with that
part of the experiment, but there was little evidence for genetic variation in
the active immune response. Our final experiment, conducted in cooperation
with Agriculture Canada in Ottawa, involved the inheritance of active and
passive immunity in sheep. Pregnant ewes were vaccinated with egg albumin,
and their immune response to this foreign protein was measured. Differences
were moderately to highly heritable. Subsequently, their lambs were measured
for egg albumin antibodies, which they had acquired from colostrum; estimated
heritability for this trait was about .30. The goal of these experiments, and
others that must follow them, is to determine whether and how ruminant animals
can be selected for enhanced survival potential from a more efficient and
effective immune system.
PREDICTING BULL FERTILITY FROM FLOW CYTOMETRIC
EVALUATION OF SEMEN SAMPLES
Former graduate student Brenda Ballachey, with Don Evenson
of South Dakota State University, and
William D. Hohenboken, Department of Animal Science
Semen samples from dairy bulls widely used in artificial insemination
(and with known differences in fertility) were analyzed by new techniques
developed by Drs. Evenson and Ballachey. Results are encouraging that a
bull's subsequent fertility can be predicted by the pattern of DNA
denaturation in sperm cells, as assessed by flow cytometry. Instrumentation
to conduct the tests is expensive but the tests themselves are quick, accurate
and repeatable.
GENETIC AND MANAGEMENT ALTERNATIVES FOR COASTAL PACIFIC
NORTHWESTERN BEEF CATTLE PRODUCTION
William D. Hohenboken
Department of Animal Science
Beginning with the 1979 calving season, OSU has conducted beef cattle
breed evaluation research at the Soap Creek Ranch near Corvallis. Foundation
cows were Herefords or Angus x Hereford crossbreds, and they were mated by
artificial insemination to Simmental, Pinzgauer and Tarentaise bulls. Cleanup
bulls in early years were Herefords and Angus x Hereford crossbreds. More
recently we have used a Simmental and a Pinzgauer for this purpose. Two-yearold heifers have been mated to Angus bulls for their first calf. For second
and later calves, all cows are mated to one of the three continental European
breeds. Breeds will be compared for their effect on calf weaning weight and
growth rate and on cow reproduction, calf production and longevity. Heterosis
for calf and maternal traits also will be quantified. It will then be
possible, on paper, to compare any systematic mating system and any
combination of the breeds for sustained, annual calf production.
BEEF CATTLE HERD AGE STRUCTURES AND THE INHERITANCE OF LONGEVITY TRAITS
William D. Hohenboken, with graduate students
Deb Schons and Hajime Tanida
Department of Animal Science
Twenty-four years of records from a large Wyoming Angus ranch were
analyzed using the sort of life history statistics familiar to life insurance
actuarial specialists and wildlife managers. We computed, for example,
probabilities that a replacement heifer calf would survive in the herd to
various ages and also the probabilities that a cow surviving to any given age
would survive one year longer. Such statistics are useful to compare
attrition patterns in different herds and to study the effects of herd age
structure on herd productivity. An experiment is now nearing completion to
compute heritability estimates for longevity in that same Angus herd and in a
Hereford herd from Arizona. Different bulls in the Angus herd differed quite
dramatically in the attrition pattern of their daughters. Results suggest
that the heritability of longevity is about .20, indicating that genetic
change is possible, though it would be difficult to design the most
appropriate selection strategies.
Selenium
Safety, Bio-availability and Transfer from Cows to Calves
Don T. Campbell, Dr. John P. Maas, Roger J. Miller,
Dr. Dale W. Weber
Selenium deficiency in the Pacific Northwest
is
responsible for significant economic losses to livestock
producers.
Both acute and chronic selenium deficiency
diseases such as nutritional muscular dystrophy, weak calf
syndrome, and general unthriftiness plague the cattle
industry. Research which provides insight to the role and
interactions of selenium in each of these diseases is
vitally important to Oregon as well as to many areas of the
world. The development of economical and practical
supplementation systems is particularly important in those
species which are reared "extensively", such as the grazing
ruminant.
In a current research project, 150 brood cows and
pregnant heifers in their last trimester of gestation were
randomly assigned to one of three treatment groups. All
animals were maintained on a diet of naturally selenium
deficient grass hay, grass silage and pasture. Treatment
group 0 received no supplemental selenium. Treatment group
1 received supplemental selenium as sodium selenite in an
orally administered intra-ruminal sustained release bolus
(DURA-SE). Treatment group 2 received supplemental selenium
as elemental selenium via 2 iron based ruminal pellets
(PERMA = SE). Blood samples are being collected from a subset
of twenty animals from each treatment group at 0, 1, 2, 4,
and 7 months of the trial. These samples will be analyzed
for whole blood selenium to determine the safety and
bioavailability of each of the treatments. This portion of
the trial is in accordance with the Food and Drug
Administration requirements for the approval of the DURA-SE
bolus. Blood samples are being collected from calves,
corresponding to the treatment group subsets, at birth and
again 24-72 hours post suckling. Colostrum samples are
being taken from these cows at parturition. These samples
will be analyzed for selenium levels and will provide
information regarding the transfer of selenium across the
placenta and through the colostrum. An additional sample at
24-72 hours post suckling will be analyzed for creatine
kinase to evaluate muscle degeneration across treatment
groups.
This research will provide information on the bioavailability of two forms of selenium and on the process of
selenium transfer from cows to calves during the last
trimester of pregnancy. Understanding this process may
allow researchers to determine procedures to eliminate
mortality of the neonate from selenium deficiency diseases
by determining appropriate supplementation schedules.
Comparison of Wheat with Two Commonly Used Grains
in a Finishing Ration
Wade Nichols
Graduate Student
Dr. Dale Weber
Associate Professor
Introduction
Wheat is a valuable livestock feed; however, in most
cases it is priced out of the feed grain market due to its
value as human food. Because of an increase in
tecnological production, decreased exports, and recent farm
can now be considered again as an
wheat
programs,
U.S.
the
In
cattle.
for
alternative feed
grain
approximatley one-third of the annual wheat crop is used
domestically for human food and seed purposes. The
remaining two-thirds normally must be exported and/or used
domestically as livestock feed. In recent years ending
stocks have almost equaled total annual usage (U.S.D.A.E.R.S. Statistical Reporting Service 1986).
Trials have demonstrated that the old "rule of thumb"
of feeding a maximum of 20-30% wheat in a ration is a
fallacy. Wheat has been fed as high as 80-100% of the
grain portion of the fattening ration with no adverse
disturbances (J.J. Martin et al., 1985;, W.R. Backus et
al., 1980). The best results however have been achieved
with a mixture containing 50-75% wheat (0.0. Thomas et
al., 1966; E.C. Prigge et al., 1980)
Some metabolic differences are observed in cattle when
utilizing wheat rations. The ruminal pH is depressed,
while the ruminal ammonia concentrations are greater in
cattle fed wheat rations. There seems to be no significant
differences in molar ratios of Volatile Fatty Acids (VFA),
however, the concentration of VFA's is greater with cattle
fed wheat rations (R.R. Oltjen et al., 1966; S.G. Reddy
et al., 1975). To reduce metabolic stress the use of
ionophores and buffers have been recommended. The problems
that occurred in the pre-ionophore era, such as, acidosis
or problems associated with extremely fast rumen
fermentation have been dramatically reduced today (W.J.
Pryor et al., 1975; D.R. Gill 1985)
The processing requirements of wheat are minimal. It
seems that wheat is so highly digestable that regardless of
how it is processed, it is difficult to improve the feed
value (R.R. Christiansen et al., 1974; J.C. Aimone et
al., 1977).
Can wheat really be economical in certain situations?
It seems that this question, like agriculture itself, is
cyclic in nature. This question has been asked every 10-15
years, and similarly research with wheat also follows this
pattern, as in the early 60's, 70's, and now in the early
to middle 80's.
Trial
In a finishing ration trial wheat was compared with
two commonly used grains: corn and barley. The trial was
conducted in two parts.
Part 1.) Feedlot Comparisons
Materials and Methods
Forty-four head of cross-bred steers from the Soap
Creek Ranch at Oregon State University were stratified by
weight and allotted to 9 groups. The 9 groups were then
randomly assigned a pen number followed by a random
assignment to 1 of 3 treatments. The finishing ration
treatments consisted of: (1) 70% corn; (2) 70% barley; and
(3) 70% wheat. In addition to the grain, the pelleted
treatment diets contained 17% oats, 10% alfalfa hay, and 3%
dry additives. The diets were isonitrogenous. Daily feed
intake and individual weights were recorded every 28 days.
The steers remained on feed until they were finished, which
was determined by visual appraisal and an ultrasonic back
fat measurement with 0.3 inches as a minimum. The feedlot
parameters measured were average daily gain (ADG), feed to
gain ratio (F/G), and days on feed. The carcass parameters
used included dressing percent, rib eye area (REA), percent
kidney, pelvic, and heart fat (% KPH), backfat thickness
(B.F.), quality grade (Q-G), and yield grade (Y-G).
Results
Table 1 illustrates the results after the steers had
been on feed 84 days. The results indicate that wheat was
utilized more efficiently having a superior F/G ratio,
however
the ADG's were not appreciably different (A
been
statistical analysis of these trials has
not
completed).
Table 1.) Steers Progress after Eighty-four Days on Feed
Ration
Barley
Corn
Wheat
Number
14
15
15
Initial wt.
lbs.
877.92
880.00
884.80
Ending wt.
lbs.
1171.71
1171.33
1176.73
ADG
lbs.
3.49
3.46
3.48
F/G
lbs.
5.92:1
5.77:1
5.49:1
The entire feeding period lasted 135 days. At this
time the last steer was slaughtered and results were
tabulated. Table 2 illustrates the final feedlot totals
and the carcass information. The 135 day feedlot
performance is somewhat lower than the 84 day period due to
the incidence of "stragglers" or those steers that required
a longer period of time in which to finish. The final
results indicate no appreciable differences in the three
different diets. All parameters measured are approximately
equal.
Table 2.) Feedlot Totals and Carcass Information of Steers
on Feed
(b)
(a)
Ration End/wt. ADG F/G Dress % REA %KPH B.F. Q-G Y-G
In.
Lbs. Lbs.
Lbs.
11.93 3.01
.45
3.0
12.96
62.35
6.83
3.02
Barley 1205
2.82
11.66
.40
3.0
13.38
62.17
6.78
3.08
1214
Corn
2.75
12.20
.43
2.9
13.76
62.65
6.82
2.94
1194
Wheat
a.
b.
measured at the 12th rib
11 = good plus, 12 = choice minus
Part 2.) Rumen Parameters as Affected by Three
Treatment Diets.
Materials and Methods
head of 3-year-old heifers that were rumen
Six
fistulated and spayed, were randomly assigned to 3
different groups followed by random assignment to 1 of 3
treatments (treatments consisted of the same rations as in
part 1). The treatments were then rotated such that all
groups would receive each treatment. The animals received
each treatment for 28 days followed by the subsequent
rotation. At the beginning of each 28-day period the
ration consisted of grass hay only, for 3 days. The
treatment diets were gradually increased until 10 days
before the end of the period, at which time the heifers
received 15 lbs/head/day of the treatment diet only. Rumen
fluid samples were collected at the conclusion of each 28
day period. The samples were collected at the following
hours: 0, 2, 4, 8, and 12. Zero hour represents the time
just prior to feeding in the morning and the subsequent
hours are after the time zero. At the time of collection,
rumen pH was determined for each animal on each treatment.
The samples were then strained and subsampled into 5 ml
vials. At that time phosphoric acid was added to stop all
microbial activity. The vials were then labeled and frozen
for future use.
Results
The wheat diet was consistently lower in pH at all
sample times than corn and barley which remained
approximately equal. The lower pH levels persisted even
though the rations were buffered with both a rumen buffer
and a lower intestine buffer. Table 3 illustrates the
rumen pH at the different sampling periods. The pH
consistently dropped after feeding for all diets and raised
throughout the day as digestion progressed. The decrease
may be due to an increase in VFA concentration as reported
earlier. A pH of 6-6.8 has been shown to be optimal for
the rumen and rumen microbial function.
Table 3.) Rumen pH at Time of Sampling the Different Diets
Sampling Times
Ration
0
2
4
8
12
6.54
6.61
6.17
6.97
6.94
6.71
pH Values
Barley
Corn
Wheat
6.68
6.84
6.65
6.23
6.24
5.92
6.17
6.19
5.74
The treatment diets were analyzed for digestibility by
using the In Vitro method of the Modified Tilley and Terry.
Each diet was replicated 4 times in each type of rumen
fluid (corn, wheat, or barley). While the digestibilities
are low, the relative differences between the diets are
what should be emphasized. The digestibilities between the
three rations are very similiar and probably not
statistically different. This is reasonable since all
diets were pelleted and therefore easily accessible to
rumen microorganisms. Also since the diets were pelleted
the passage rates are assumed to be similiar. Table 4
gives the differences or the similarities in digestibilities of the rations.
Table 4.) Digestibilities of the Diets in Rumen Fluid of
the Three Different Grains.
Rumen
Fluid Type
Ration
Percent Digestibility
Barley
Corn
Wheat
Barley
Corn
Wheat
Barley
Corn
Wheat
Barley
Corn
Wheat
49.55
55.59
51.03
43.49
42.61
44.53
42.61
41.17
41.77
Ration Average
Barley
Corn Wheat
45.22
46.46
45.78
The rumen fluid will be analyzed using gas
chromotography. The parameters to be determined by this
analysis will be the concentrations and ratios of the VFA's
(propionic acid, acetic acid, butyric acid), the branch
chained VFA's (isovaleric acid, valeric acid, isobutyric
acid), and lactic acid.
Liver abscesses were not a problem during this trial.
This was probably due to the addition of the buffers and
the ionophore. The short period of time that these cattle
were on feed could also be a factor.
Summary
Although part 2 of this trial is not yet complete, it
is not anticipated that any significant differences between
the treatment diets will exist. This is based on the
results of part 1 and the digestiblities of the different
diets.
It is believed that the use of these three grains at
this level are similiar in respect to feedlot performances.
A producer may price optimize when buying and therefore
increase the potential for a greater profit margin.
There are a few management practices to be followed
when using wheat as a grain source. The management
practices that are recommended are:
1) Use an Ionophore (Rumensin or Bovatec)
2) The use of rumen and lower intestine buffers are
recommended (Sodium Bicarbonate, and Limestone)
3) The use of an antibiotic to help control liver abscesses
4) Wheat should be mechanically processed; crimped,
rolled, etc.
5) Allow cattle to become accustomed to finishing ration
gradually or work wheat into the finishing ration slowly
6) Do not allow cattle to go hungry. Feed 2 or more
times/day and keep bunks clean of old feed
7) Give cattle access to plenty of fresh water
8) Keep roughage levels at 10-12% to insure proper rumen
stimulation.
Literature Cited
Aimone J.C. and D.C.Wagner. 1977. Micronized Wheat I.
Influence on Feedlot Performance, Digestability, VFA and
Lactic Acid Levels in Cattle. J. Anim. Sci. 44:1088
Backus W.R., J.T. Fain, J.M. Anderson and N.W. Robinson.
1980 Substitution of Whole Wheat for Whole Corn in Finishing
Rations for Yearling Cattle. Rep. Tenn. Agr. Exp. Stn.
Apr/June 80:114.
Christiansen R.R. and D.L. Wagner. 1974. Reconstituted
Wheat. I. Influence on Feedlot Performance of Cattle. J.
Anim. Sci. 38:456.
Gill D.R. 1984. Rumensin and Bovatec Blazed the Trail.
Successful Farming. Dec. 84:B4.
Martin, J.J., C.A. Strasia, F.N. Owens and D.R. Gill. 1985.
Wheat to Corn Ratios for Feedlot Cattle. Anim. Sci. Res.
Rep. 85:MP-117.
Oltjen, R.R., P.A. Putnam, E.E. Williams and R.E. Davis.
1966. Wheat vs. Corn in All-Concentrate Cattle Rations. J.
Anim. Sci. 25:1000.
Prigge, E.C. and J.L. Thompson. 1980. Performance of Wheat,
Barley Improved when Combined. Feedstuffs Aug. 80 52:33.
Pryor, W.J. and L. Laws. 1972. The Effect of Grain to
Roughage Ratio, Grain Processing and Sodium Bicarbonate
Supplementaion on Productivity and Health in Steers.
Australian Vet. J. 48:500.
Reddy, S.G., M. L. Chen and D.R. Rao. 1975. Repacement
Value of Triicale for Corn and Wheat in Beef Finishing
Rations. J. Anim. Sci. 40:940.
Thomas, 0.0., B. Warley, B.R. Geissler, and W.L. Mies.
1966. Substution of Wheat for Barley in Cattle Fattening
Rations. Montana Agr. Exp. Stn. Res. Rep. May 66:32.
U.S.D.A. Economic Research Service, Statistical Reporting
Service. 1986. Agr. Outlook. M 86:A0-117.
Regulation of Corpus Luteum Function
Fredrick Stormshak
Department of Animal Science
Oregon State University, Corvallis
Research is being conducted to examine the effects of
gonadotropin releasing hormone (GnRH or Cystorelin) on
progesterone secretion by the corpus luteum of the beef cow
during various days of the estrous cycle. Results of
experiments indicate that GnRH administered to beef cows at
the beginning of the estrous cycle interferes with the
ability of the developing corpus luteum to secrete normal
quantitites of progesterone. Progesterone is the hormone
that is essential for maintenance of pregnancy. Another
line of research involves studies to elucidate the role of
prostaglandin F (lutalyse) in promoting secretion of
oxytocin by the cow corpus luteum. Oxytocin released by
the corpus luteum is believed to act on the uterus, causing
the latter organ to secrete increased quantities of
prostaglandin F 2 which then bring about regression of the
corpus luteum ana the end of the estrous cycle.
This research is aimed at elucidating the factors that
can impair or enhance the function of the cow corpus luteum
and whether such alteration of corpus luteum function can
affect the incidence of early embryonic mortality in
cattle.
It is anticipated that the research will lead to more
effective methods of regulating estrous behavior and of
preventing early embryonic mortality in cattle.
Fred Menino; Assistant professor/Animal Science; Embryo physiologist
The research interests of our laboratory cover a wide spectrum of embryorelated phenomena in a variety of species. Current projects underway include
nuclear transplantation, modulation of embryo development and cell division
with lectins and growth factors, plasminogen activation and its significance
in the early embryo, evaluation of embryo-uterine interaction in early
development, factors affecting the superovulatory response, trophoblast cell
culture and embryonic micromanipulation and microdissection. Techniques
routinely conducted in our laboratory include embryo and tissue culture,
enzyme assays, embryo micromanipulation and gel electrophoresis.
The major applications of this work are aimed at improving the
reproductive efficiency of the farm female and advancing the technology of
embryo transfer.
Interaction of Diet and Hormones in Controlling the
Postpartum Period of Beef Cows
Fredrick Stormshak, Harley A. Turner and Martin Vavra
Department of Animal Science, Corvallis, and
Eastern Oregon Agricultural Research Center, Union
Studies have been conducted to investigate the effects
of a hay plus native pasture (limited feed) vs hay (full
feed) management scheme on return to estrus of postpartum 2
year old and mature Hereford x Simmental-cross beef cows
maintained at the Eastern Oregon Agricultural Research
Center, Union. Postpartum cows were bled weekly and the
serum assayed for progesterone to monitor for onset of
cyclic activity. Regardless of the management scheme,
mature cows on both feeding regimens and full fed heifers
returned to estrus earlier than did the limited fed 2 year
old heifers. Only one of ten 2 year old heifers on limited
feed was detected in estrus prior to June 1.
A study was also conducted to examine the effects of
the suckling stimulus on gonadotropin releasing hormone
(GnRH)-induced release of luteinizing hormone (LH) from the
anterior pituitary. The act of suckling did not interfere
with injected GnRH-induced release of LH. However, release
of LH was markedly reduced at one week after parturition
compared to the release of LH that occurred at two weeks
postpartum. These data suggest that the function of the
anterior pituitary of beef cows may be depressed shortly
after calving.
The aim of this research is to identify those environmental and physiological factors that affect the duration of
the postpartum anestrus period in beef cattle, especially in
the 2 year old heifer. It is anticipated that continued
research in this area will result in methods of shortening
the postpartum period in beef cows, thus reducing the number
of cows that fail to conceive due to lack of estrus during
the breeding season.